Approved Final TMDLs

Water Quality Analyses (WQA) with EPA Concurrence of MDE's Findings: Lower North Branch Potomac River

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The Lower North Branch Potomac River watershed is located in the North Branch Potomac River Sub-basin within Maryland. The watershed area covers 35,514 acres in Allegany County, Maryland, forming a portion of the border between Maryland and West Virginia. The Lower North Branch Potomac River watershed drains north to southwest and north to southeast.

The Lower North Branch Potomac River (basin code 02141001), located in Allegany County, Maryland, was identified on the State’s list of water quality limited segments (WQLSs) as impaired by low pH (1996 listing), nutrients (1996 listing), sediments (1996 listing, cadmium (Cd) (1996 listing) and impacts to biological communities (2002 listing). The report available below provides an analysis of recent monitoring data to address whether the low pH impairment still remains. A data solicitation for pH was conducted by MDE and all readily available data from the past five years was considered.

The study demonstrates that the applicable aquatic life criterion for pH and the designated uses supported by this criterion are being met in the Lower North Branch Potomac River. Barring the receipt of any contradictory data, this report will be used to support the removal of the 8-digit basin from Maryland’s list of WQLSs for low pH when the Maryland Department of the Environment (MDE) proposes the revision of Maryland’s 303(d) list for public review in the future. The listings for nutrients, sediments, Cd and impacts to biological communities will be addressed at a future date.

Although the non-tidal waters of the Lower North Branch Potomac River do not display signs of impairment due to low pH, the State reserves the right to require additional pollution controls in the Lower North Branch Potomac River watershed if evidence suggests that acidity resulting in low pH from the basin is contributing to downstream water quality problems.

Water Quality Analysis of Low pH for the Lower North Branch of the Potomac River in Allegany County, MD